Explainer: How Redistricting Can Shape Elections -- and What Happens When It Does

Winning the backroom battle over reapportionment can keep a political party in power for a decade

What’s responsible for the extreme divide between Republicans and Democrats in Congress, and to a lesser extent, in Trenton? Some political observers believe part of the problem is the way we draw legislative and congressional districts. These days, it seems politicians pick their voters, not the other way around, and the result has been very few competitive contests.

What it is (in theory)

Every 10 years following the U.S. Census, redistricting commissions or state legislatures throughout the country redraw the maps for their legislative and congressional districts to adjust for population shifts and comply with various U.S. Supreme Court and state court equal-representation decisions requiring that federal and state lawmakers should represent about the same number of voters.

What really happens

Even in states like New Jersey that require bipartisan redistricting commissions with neutral tiebreakers to redraw the maps, redistricting is a highly political process in which party experts use sophisticated election data in an effort to create maps that will enable them to win the maximum number of seats while protecting their own incumbents.

Why it matters

The congressional and legislative maps drawn by redistricting commissions or by the governors and legislatures in power in 2010 to 2011 were so expertly drawn for partisan advantage that they essentially determined the partisan makeup of the U.S. House of Representatives and state legislatures for a decade -- until the next redistricting round in 2020 and 2021.

The Democratic map chosen by the New Jersey Legislative Reapportionment Commission’s neutral tiebreaker, Alan Rosenthal, is the principal reason that Republicans won the same number of legislative seats in 2013 when Gov. Chris Christie was elected in a landslide as it did when he won the governorship by a narrow margin in 2009. Republicans had a hard time choosing five Democratic-held districts that could even be considered marginally competitive in an effort to reverse the Democrats’ 24-16 control of the state Senate.

Sizing up the competition

Nationwide, no more than 20 of 435 House districts are considered competitive by most pols. Republican control of the U.S. House of Representatives is virtually assured until 2022 because Republican governors and legislatures elected in the 2010 backlash against Obamacare were in full control of redistricting in traditionally Democratic states like Pennsylvania, Michigan, Wisconsin, and Minnesota, and they drew maps that sent majority Republican delegations to Washington.

Because so few congressional districts are competitive in the November general election, House incumbents only have to worry about primary challenges from left-leaning liberals or far-right conservatives in low-turnout June primaries dominated by ideological voters. Thus, gerrymandering is one of the main reasons for the extreme partisanship in Congress, as House members hew to the rigid party line rather than seeking the bipartisan compromises that voters tell pollsters they want.

The 1966 Constitutional Convention

New Jersey convened a constitutional convention in 1966 with the limited purpose of deciding how to redraw the state’s legislative districts in the wake of a series of U.S. Supreme Court rulings in “one man, one vote” cases made it clear that the system of electing one state senator from each county was unconstitutional. For decades, the system had guaranteed GOP control of the New Jersey Senate in a state whose electorate was relatively evenly split between Democrats and Republicans because 11 rural Republican counties representing 20 percent of the state’s total population controlled the 21-member Senate.

The Constitutional Convention recommended that New Jersey establish a Legislative Redistricting Commission with 10 members -- five Democrats and five Republicans -- with a neutral 11th member appointed by the New Jersey Supreme Court chief justice to serve as the tiebreaking vote. The Chief Justice appointed a political science professor as the tiebreaker for the first commission, establishing a precedent that has continued for four decades.

How legislative redistricting works in NJ

Democrats and Republicans reached agreement on the first map without needing the neutral tiebreaker’s vote, but since 1980, the Democratic and Republican commissioners have essentially developed into separate caucuses with their own staffs that develop maps designed not only to maximize the number of seats their party will win, but also to satisfy the priorities and inclinations of the neutral tiebreaker.

Democrats won the 2011 redistricting round by developing a map that appealed to the stated belief of the late Alan Rosenthal, the Rutgers University political science professor who served as the neutral tiebreaker, that preserving incumbency and keeping most voters in the same districts should be a top priority, and not the creation of competitive districts.

In fact, most political observers felt that the Republicans lost the redistricting battle when they included Rosenthal’s name on the proposed list of neutral tiebreakers they submitted.

The map Rosenthal approved was so favorable to incumbents that no more than five of the 40 districts could even be considered marginally competitive, thus preserving the Democratic majorities already in place in both houses of the Legislature in 2009 even when Christie won reelection by a landslide in 2013.

How congressional redistricting works in NJ

Even after the Constitutional Convention of 1966, the New Jersey Legislature and governor continued to approve congressional redistricting maps by legislation following the 1970 and 1980 censuses.

In 1991, however, Democrats lost both houses of the Legislature to the Republicans in the anti-Florio tax backlash. During the “lame duck” session in December, Florio and the Democratic Legislature approved a bill establishing a Congressional Reapportionment Commission along the same lines as the legislative redistricting commission established by the Constitutional Convention.

The Congressional Reapportionment Commission has 14 partisan members – seven Democrats and seven Republicans – and a neutral tiebreaker also appointed by the Supreme Court chief justice. The commission has now redrawn New Jersey’s congressional districts three times.

Rutgers-Newark Law School Dean John Famer Jr. served as the neutral tiebreaker in the last round, when the commission had the task of consolidating New Jersey’s 13 House districts into 12 because the state’s stagnant population growth compared to other states cost it a district in the reapportionment of the 435 House seats.

Farmer chose a map proposed by the Republicans that effectively combined the seats of two Democratic congressmen, Rep. William Pascrell of Passaic County and Rep. Steven Rothman of Bergen County, into a single district. Although the district was Bergen-dominated, Pascrell waged an aggressive campaign and defeated Rothman in the Democratic primary to stay in Congress. The other 11 House incumbents all won reelection, giving New Jersey a 6-6 congressional delegation split.

How it works in other states

While most states allow their governors and legislatures to draw their legislative and congressional redistricting maps, 19 other states also entrust legislative and/or congressional redistricting to commissions.

Like New Jersey, Connecticut, Pennsylvania, Hawaii, Montana, Maine, and Vermont have commissions with neutral tiebreakers. Idaho, Washington State, Illinois and Missouri have bipartisan commissions made up of equal numbers of Democrats and Republicans. These commissions are intended to produce maps that are fair to both parties.

There are three reform models. California and Arizona have citizens commissions that are designed to promote competitive districts and limit the ability of political parties to protect their incumbents, while Iowa entrusts redistricting to a commission made up of professionals from its nonpartisan Office of Legislative Services.
Alaska, Colorado, Arkansas, Ohio, Indiana, and Texas have mixed-model commissions whose representation generally reflects partisan control in those states, and thus produces maps gerrymandered in favor of the party in power that are little different than those drawn up by governors and legislatures in states with one-party control.